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Posted: Fri Sep 02, 2011 10:41 pm
by Gun Freak
I'd scrap that valve too. A 2 foot 2 inch chamber on a 2" piston valve would fill quickly and provide good power. My fill flow control valve was half open in this video.
[youtube][/youtube]

Posted: Fri Sep 02, 2011 10:52 pm
by pneumaticcannons
what is there to patent on the gun?

Posted: Sat Sep 03, 2011 4:19 am
by Crna Legija
Gun Freak wrote:I'd scrap that valve too. A 2 foot 2 inch chamber on a 2" piston valve would fill quickly and provide good power. My fill flow control valve was half open in this video.
yeah if you want a fast semi that seal quick make a piston valve. Only allow the piston to move 1/4 if your barrel ports diameter and use GGDT to optimize the guns chamber barrel ratio.

also stop double/triple posting.

Posted: Sat Sep 03, 2011 6:11 am
by CannonCreations
Yeah, I think i will work on making a piston valve, thanks for the help guys. right now I use a 4" by 3ft chamber and I dont need that much air, so I will cut it down, and work on a piston valve. And sorry I didnt mean to double post, how do I delete posts? My internet and computer were messing up, and it was doing some refresh, and reload thing when i hit submit, and it would post twice, so i would change the second message to something else

Posted: Sat Sep 03, 2011 6:17 am
by Crna Legija
CannonCreations wrote:Yeah, I think i will work on making a piston valve, thanks for the help guys. right now I use a 4" by 3ft chamber and I dont need that much air, so I will cut it down, and work on a piston valve. And sorry I didnt mean to double post, how do I delete posts? My internet and computer were messing up, and it was doing some refresh, and reload thing when i hit submit, and it would post twice, so i would change the second message to something else

As i said use GGDT to optimize your barrel to chamber ratio.

Posted: Sat Sep 03, 2011 6:25 am
by CannonCreations
Yeah i will use that, Another question though, what material should i use for the piston itslef? what works good to make sure it seals properly and wont break? I was thinking some sort of rubber sheet, or O-ring but dont know where to find them?

Posted: Sat Sep 03, 2011 6:35 am
by Crna Legija
CannonCreations wrote:Yeah i will use that, Another question though, what material should i use for the piston itslef? what works good to make sure it seals properly and wont break? I was thinking some sort of rubber sheet, or O-ring but dont know where to find them?
Look around though the showcase and search there plenty of threads about what can be use.

Posted: Sat Sep 03, 2011 6:41 am
by CannonCreations
Yeah I have been looking, I see people using Very large O-rings, and I dont know where to go to get them, i would like to build a washer and oring piston

Posted: Sat Sep 03, 2011 6:49 am
by jackssmirkingrevenge
CannonCreations wrote:Yeah, I think i will work on making a piston valve, thanks for the help guys. right now I use a 4" by 3ft chamber and I dont need that much air, so I will cut it down, and work on a piston valve.
Far too much volume, as Crna suggested download GGDT, it's a great program for making virtual models of launchers in order to optimise performance before you actually get building.
And sorry I didnt mean to double post, how do I delete posts? My internet and computer were messing up, and it was doing some refresh, and reload thing when i hit submit, and it would post twice, so i would change the second message to something else
Only moderators can delete posts.
I see people using Very large O-rings, and I dont know where to go to get them
Have a look on eBay, plenty of cheap sets which include large o-rings.

Posted: Sat Sep 03, 2011 6:50 am
by Crna Legija
CannonCreations wrote:Yeah I have been looking, I see people using Very large O-rings, and I dont know where to go to get them, i would like to build a washer and oring piston
You don't need O-rings just a very close fit. If you do use the bolt washer way you can squash sheet rubber discs in between the washers, that way when you tighten it nuts it will get tighter fit so you can adjust them to fit perfectly.

Posted: Sat Sep 03, 2011 8:57 am
by Gun Freak
Actually, while building my last bolt washer piston, I found out that a check valve could be made with rubber washers the same size as the sealing face. I will draw it up in a second.

Alrighty here it is, if you understood my last diagram you should understand this one too. Very simple. You need three of the rubber washer setups.

Posted: Sat Sep 03, 2011 11:07 am
by CannonCreations
why do I need three? washers on the bolt? and how do i make sure that the pisotn goes back when the vlave is piloted? doesn't the washer on the left have to be biger than that of the right, so that it will go in that direction since it would have more force?

Posted: Sat Sep 03, 2011 11:15 am
by jackssmirkingrevenge
CannonCreations wrote:doesn't the washer on the left have to be biger than that of the right, so that it will go in that direction since it would have more force?
The barrel internal diameter should be smaller than the main piston diameter.

Posted: Sat Sep 03, 2011 11:22 am
by Gun Freak
Jack, the rubber washer on the left was the sealing face. No need to add one, but it could be changed to use a barrel other than 1.5".

Posted: Sat Sep 03, 2011 11:26 am
by jackssmirkingrevenge
Gun Freak wrote:Jack, the rubber washer on the left was the sealing face.
Noticed after I made the diagram when I saw dewey-1's rendering :)